AU2017242170A1

AU2017242170A1 - Fiber-reinforced layer for conveyor belt, and conveyor belt

Info

Publication number: AU2017242170A1
Application number: AU2017242170A
Authority: AU
Inventors: Nana Tashiro
Original assignee: Yokohama Rubber Co Ltd
Current assignee: Yokohama Rubber Co Ltd
Priority date: 2016-03-31
Filing date: 2017-02-28
Publication date: 2018-09-27
Also published as: JP2017179668A; JP6724489B2; CN108712991A; WO2017169465A1

Abstract

Provided are a conveyor belt fiber-reinforced layer and conveyor belt such that the tear resistance on both widthwise ends of the conveyor belt can be improved. A fiber-reinforced layer 3 has a woven structure having warps 4 extending in the longitudinal direction and wefts 5 extending in the width direction. The elongation of the fiber-reinforced layer 3 at both widthwise end parts R1 under one-tenth load of the cutting load in the longitudinal direction is set from 110% to 200% inclusive of the elongation thereof at the widthwise middle section R2. The fiber-reinforced layer 3 is embedded in the conveyor belt 1 as a tension member 2 so that the extension direction of the warps 4 is in the belt longitudinal direction.

Description

Technical Field [0001]

The present invention relates to a fiber reinforced layer for a conveyor belt, and a conveyor belt, and more specifically, relates to a fiber reinforced layer for a conveyor belt, capable of improving tear resistance at both end portions in the width direction of a conveyor belt, and to a conveyor belt.

Background Art [0002]

At a conveyance side of a conveyor belt, both end portions in the belt width direction are bent upward with respect to a central portion to form a trough shape, and the conveyor belt is used. Therefore, tensile strain becomes larger at both end portions in the belt width direction than at the central portion, and tears attributed thereto are easily generated.

[0003]

Cores that bear the tension when stretched and installed are embedded in conveyor belts, and various conveyor belts that manipulate these cores are proposed (for example, see Patent Documents 1 and 2). Patent Document 1 proposes that in order to improve productivity without losing the buckling resistance of the core, the warp threads and weft threads of a core having a plain weave structure are not twisted, and the elongation of the conveyor belt is limited to a specific range. Patent Document 2 proposes that in order to improve the quality of a core that has adopted polyester fibers as the weft thread, the fiber fineness and number of twists of the weft threads are limited to a specific range.

[0004]

However, these proposed cores do not focus attention on tears that are generated at both end portions in the belt width direction, and therefore when the conveyor belt is in a trough shape, tensile strain at both end portions in the belt width direction becomes relatively high. Therefore, the tear resistance of both end portions in the belt width direction cannot be improved.

Citation List Patent Literature [0005]

Patent Document 1: JP 2009-274798 A Patent Document 2: JP 2014-201853 A

Summary of Invention Technical Problem [0006]

An object of the present invention is to provide a fiber reinforced layer for a conveyor belt, capable of improving the tear resistance of both end portions in the width direction of the conveyor belt, and a conveyor belt.

Solution to Problem [0007]

To achieve the above-described object, the fiber reinforced layer for a conveyor belt of the present invention has a woven structure with warp threads extending in the longitudinal direction, and weft threads extending in the width direction, and the elongation of the fiber reinforced layer at both end portions in the width direction under a one-tenth load of the breaking load in the longitudinal direction is from 110% to 200% of the elongation at the central portion in the width direction.

[0008]

With the conveyor belt of the present invention, the fiber reinforced layer for a conveyor belt is embedded as a core with the extension direction of the warp threads oriented in the belt longitudinal direction.

Advantageous Effects of Invention [0009]

According to the present invention, in the width direction of the fiber reinforced layer, the elongation at a relatively low tensile load in the longitudinal direction becomes relatively larger at both end portions. Therefore, when the fiber reinforced layer is embedded as a core in the conveyor belt with the extension direction of the warp threads being oriented in the belt longitudinal direction, elongation of both end portions in the belt width direction becomes relatively larger. Through this, even when the conveyor belt is used in a trough shape, the tensile strain of both end portions in the belt width direction is alleviated, and therefore tear resistance at both end portions in the belt width direction can be improved.

[0010]

Here, the woven structure is favorably formed as a 2/2 broken twill structure. Such a configuration is advantageous in improving the impact resistance of the conveyor belt.

[0011]

The specifications are such that the warp threads at both end portions in the width direction are made from polyamide fibers, for example, and the warp threads at the central portion in the width direction are made from polyester fibers, for example. According to these specifications, when the conveyor belt is in a trough shape, the elongation at both end portions in the belt width direction can be easily made relatively larger.

[0012]

With the conveyor belt of the present invention, the core has a multilayer structure in which a plurality of reinforced layers are laminated, and the specification can also be such that the outermost circumferential reinforced layer of this multilayer structure is the fiber reinforced layer for a conveyor belt. According to this specification, the effect of the fiber reinforced layer of the present invention can be efficiently obtained.

Brief Description of Drawings [0013]

FIG. 1 is a cross-sectional view illustrating a conveyor belt in which the fiber reinforced layer for a conveyor belt of the present invention is embedded.

FIG. 2 is a plan view of the conveyor belt illustrated in FIG. 1.

FIG. 3 is an explanatory drawing illustrating the fiber reinforced layer of FIG. 1 in an enlarged plan view.

FIG. 4 is an explanatory drawing illustrating a state where the conveyor belt of FIG. 1 is stretched and installed.

FIG. 5 is a cross-sectional view along A-A of FIG. 4.

Description of Embodiments [0014]

A fiber reinforced layer for a conveyor belt and a conveyor belt according to the present invention will be described below based on embodiments with reference to the drawings.

[0015]

A fiber reinforced layer 3 for a conveyor belt (hereinafter, referred to as the fiber reinforced layer 3) of the present invention is embedded as a core 2 in a conveyor belt 1 of the present invention as illustrated in FIGS. 1 and 2. The core 2 is a member which bears the tension that is generated in the conveyor belt 1 when stretched. An upper cover rubber 6 and a lower cover rubber 7 are respectively disposed above and below the core 2, and the core 2, the upper cover rubber 6 and the lower cover rubber 7 are integrated through vulcanization bonding. The core 2 is continuous in the belt longitudinal direction, and the dimension in the width direction is somewhat smaller than the belt width. Through this, both ends of the conveyor belt 1 in the width direction become edge rubber at which the core 2 is not present.

[0016]

In this embodiment, the core 2 is a four-layer structure in which one layer of the fiber reinforced layer 3 of the present invention and three layers of a separate fiber reinforced layer 3a are laminated. The fiber reinforced layer 3 of the present invention is the outermost circumferential reinforced layer of the core 2. The number of fiber reinforced layers 3 and 3a that are laminated to configure the core 2 is determined by the required performance (for example, rigidity, and elongation) of the conveyor belt 1, is not limited to the four layers as with the present embodiment, and can be one layer or other pluralities of layers.

[0017]

As illustrated in FIG. 3, the fiber reinforced layer 3 of the present invention has a woven structure with warp threads 4 extending in the longitudinal direction, and weft threads 5 extending in the width direction. The fiber reinforced layer 3 is embedded with the extension direction of the warp threads 4 oriented in the belt longitudinal direction. That is, the longitudinal direction of the warp threads 4 are oriented in the longitudinal direction of the conveyor belt 1, and the longitudinal direction of the weft threads 5 is oriented in the width direction of the conveyor belt 1.

[0018]

In this embodiment, the woven structure of the fiber reinforced layer 3 is formed as a 2/2 broken twill structure. In addition, as the woven structure of the fiber reinforced layer 3, other woven structures such as a plain weave structure can be adopted.

[0019]

The fiber reinforced layer 3 is such that an elongation El at both width direction end portions RI under a one-tenth load of a breaking load in the longitudinal direction of the fiber reinforced layer 3 is larger than an elongation E2 of a central portion R2 in the width direction, and is from 110% to 200% of the elongation E2. The elongation of the fiber reinforced layer 3 under a one-tenth load of the breaking load in the longitudinal direction is measured, for example, through a test in conformance with the JIS K6322 belt tensile test. [0020]

The central portion R2 in the width direction of the fiber reinforced layer is, for example, a region from around 50% to 60% of an entire width WR of the fiber reinforced layer 3 centered on a center CR in the width direction of the fiber reinforced layer 3. Both end portions Rl in the width direction are regions other than the central portion R2 in the width direction, and therefore the end portions Rl are respective regions roughly from 20% to 25% of the entire width WR from respective both ends in the width direction of the fiber reinforced layer 3. The entire width WR of the core 2 (fiber reinforced layer 3) is slightly smaller than an entire width WB of the conveyor belt 1, and is substantially the same. Furthermore, the center CR in the width direction and a center CB in the belt width direction are at generally matching positions. Thus, both end portions Rl in the width direction of the fiber reinforced layer 3 are embedded in both end portions Z1 in the belt width direction of the conveyor belt 1, and the central portion R2 in the width direction of the fiber reinforced layer 3 is embedded in a central portion Z2 in the belt width direction of the conveyor belt 1.

[0021]

To make the elongation El at both end portions Rl in the width direction relatively larger than the elongation E2 of the central portion R2 in the width direction, for example, the materials of the warp threads 4 in each of the both end portions Rl in the width direction and in the central portion R2 in the width direction are varied, and a material with relatively large elongation is used for both end portions Rl in the width direction. More specifically, the warp threads of both end portions Rl in the width direction are made of polyamide fibers, and the warp threads 4 at the central portion R2 in the width direction are made of polyester fibers. A multifilament yarn in which a plurality of polyamide fibers are twisted, or a monofilament yarn can also be used for the warp threads 4 at both end portions Rl in the width direction. A multifilament yarn in which a plurality of polyester fibers are twisted, or a monofilament yarn can also be used for the warp threads 4 at the central portion R2 in the width direction. As the polyamide fiber, nylon 6, and nylon 66, can be used, for example.

[0022]

As illustrated in FIGS. 4 and 5, the conveyor belt 1 is stretched between pulleys 8a and 8b and used. Furthermore, at a conveyance side on which an object 10 to be conveyed is placed and transported, lower surfaces of both end portions Zl in the belt width direction are supported by support rollers 9 having a rotation shaft that is inclined at a predetermined angle a with respect to a horizontal plane, and a lower surface of the central portion Z2 in the belt width direction is supported by a support roller 9 having a rotation shaft which is horizontal. Through this, both end portions Zl in the belt width direction (both end portions RI in the width direction) are bent upward with respect to the central portion Z2 in the belt width direction (central portion R2 in the width direction), and the conveyor belt 1 becomes a trough shape and is used.

[0023]

Therefore, the tension borne by the core 2 becomes relatively larger at the both end portions Zl in the belt width direction (both end portion RI in the width direction) than at the central portion Z2 in the belt width direction (central portion R2 in the belt width direction). In association therewith, the tensile strain becomes larger at both end portions Zl in the belt width direction (both end portions RI in the width direction) than at the central portion Z2 in the belt width direction (central portion R2 in the width direction), and therefore tears are easily generated. That is, tears extending in the belt width direction and attributed to the relatively large tensile strain are easily generated at both end portions Zl in the belt width direction.

[0024]

However, with the present invention, the fiber reinforced layer 3 embedded as the core 2 is such that the elongation under a one-tenth load of the breaking load in the longitudinal direction of the fiber reinforced layer 3 becomes relatively larger at both end portions RI in the width direction than at the central portion R2 in the width direction. Therefore, even when the conveyor belt 1 becomes a trough shape and is used, the fiber reinforced layer 3 is relatively largely elongated at both end portions Zl in the belt width direction (both end portions RI in the width direction), and thereby the tensile strain of both end portions Zl in the belt width direction is alleviated. In association therewith, the tear resistance of both end portions Zl in the belt width direction can be improved. Here, the elongation under a one-tenth load of the breaking load in the longitudinal direction of the fiber reinforced layer 3 is used because the magnitude of this one-tenth load is a level that relatively approximates the tension borne in ordinary conditions by the core 2 (fiber reinforced layers 3 and 3a) of the conveyor belt 1 when stretched and installed.

[0025]

When the elongation El at both end portions RI in the width direction of the fiber reinforced layer 3 is less than 110% of the elongation E2 at the central portion R2 in the width direction, the relative elongation of both end portions RI in the width direction with respect to the central portion R2 in the width direction is too small, and thus such an elongation El is insufficient for improving the tear resistance of both end portions Z1 in the belt width direction. On the other hand, when the elongation El at both end portions RI in the width direction exceeds 200% of the elongation E2 at the central portion R2 in the width direction, both end portions Z1 in the belt width direction deform excessively, and function as the conveyor belt 1 decreases.

[0026]

In a case where the core 2 has a laminated structure in which a plurality of reinforced layers are layered, all of the reinforced layers may be the fiber reinforced layer 3 of the present invention, but to reduce costs, some of the layers may be the fiber reinforced layer 3 of the present invention, and the remaining layers may be a separate inexpensive, general-purpose reinforced layer 3. For example, only one outermost circumferential layer may be the fiber reinforced layer 3 of the present invention, as with the present embodiment. Alternatively, only the first and second layers from the outermost circumferential surface may be the fiber reinforced layer 3 of the present invention.

[0027]

With a core 2 of a laminated structure, in a case where the conveyor belt 1 forms a trough shape, tensile strain becomes the largest at the outermost circumferential reinforced layer. Therefore, when the fiber reinforced layer 3 of the present invention is used as the outermost circumferential reinforced layer, an advantageous effect from the above-described fiber reinforced layer 3 can be efficiently obtained while minimizing the usage amount of the fiber reinforced layer 3.

[0028]

Furthermore, when the woven structure of the fiber reinforced layer 3 is made to be a 2/2 broken twill structure, the impact resistance of the conveyor belt 1 can be improved compared to a plain weave structure or the like. Tears in the conveyor belt 1 are basically attributed to localized stress concentration generated by the object 10 to be conveyed that is placed on the conveyor belt 1, and this may damage the conveyor belt 1. For cases in which stress is concentrated with a plain weave structure, the warp threads and the weft threads intersect one by one, and therefore the entire load is applied to one thread each. With a 2/2 broken twill structure, there is a portion at which the warp threads and the weft threads are arranged side by side in quantities of two each, and therefore the impact can be dispersed to the two threads thereof. Accordingly, the conveyor belt 1 (particularly the upper cover rubber 6 and the fiber reinforced layer 3) is not easily damaged.

[0029]

It is the upper cover rubber 6 that directly receives impact from the object 10 to be conveyed that is introduced onto the conveyor belt 1. Therefore, when the fiber reinforced layer 3 having a 2/2 broken twill structure is used as the outermost circumferential reinforced layer in the core 2 having a laminated structure, an advantageous effect from the above-described 2/2 broken twill structure can be efficiently obtained while minimizing the use amount of the fiber reinforced layer 3.

Examples [0030]

Six types of samples (Conventional Example, Comparative Examples 1 and 2, Examples 1 to 3) of the fiber reinforced layer for a conveyor belt were produced as shown in Table 1. Polyester fibers were used for the weft threads of all of the samples. The elongation under a one-tenth load shown in Table 1 is the elongation under a one-tenth load of the breaking load with respect to the extension direction of the warp threads of each sample, and the elongation El at the end portions in width direction and the elongation E2 at the central portion in the width direction were measured. In Table 1, the dimension of both end portions in width direction/total width is a ratio (percentage) obtained by dividing the total value of the width dimensions of both end portions in the width direction by the total width (total value obtained by adding the total value of the width dimensions of both end portions in the width direction and the width dimension of the central portion in the width direction). PET in Table 1 indicates polyester, and N66 indicates nylon 66.

[0031]

The six types of conveyor belts (belt of Conventional Example, belts of Comparative Examples 1 and 2, and belts of Examples 1 to 3) shown in Table 1 were produced using the respective samples. Four fiber reinforced layers were embedded in each of the conveyor belts, and only one of the fiber reinforced layers, namely the outermost circumferential layer, was differed. The following three types of performances were measured with respect to these conveyor belts, and the results are as shown in Table 1.

[0032] [Table 1]

	Conventional Example	Comparative Example 1	Comparative Example 2	Example 1	Example 2	Example 3
Specifications of fiber reinforced layer	Woven structure	Plain weave	<	<	<	2/2 broken twill	<
Warp thread material	End portions in width direction	PET	<	<	<	<	N66
Central portion in width direction	PET	<	<	<	<	<
Elongation (%) under one-tenth load	End portions El in width direction	2.5	3.0	5.2	3.0	<	4.0
Central portion E2 in width direction	2.5	<	<	<	<	<
E1/E2 (%)	100	120	210	120	120	160
Dimension of both end portions in width direction/total width (%)	-	60	30	30	30	30
	Belt of Conventional Example	Belt of Comparative Example 1	Belt of Comparative Example 2	Belt of Example 1	Belt of Example 2	Belt of Example 3
Lamination specifications of fiber reinforced layer	Outermost circumferential layer	Conventional Example	Comparative Example 1	Comparative Example 2	Example 1	Example 2	Example 3
Other layers	Conventional Example	<	<	<	<	<
Belt performance	Tear resistance of both end portions in width direction (index value)	100	110	110	110	120	125
Impact resistance of central portion in width direction (index value)	100	100	100	100	120	120
Creep performance (index value)	100	90	90	100	100	100

[0033]

Tear resistance of both end portions in width direction

Cut samples of each conveyor belt were used to evaluate the tear resistance in the belt width direction at the end portions in width direction of the conveyor belt. This evaluation measurement was obtained by calculating the energy required until a predetermined tear was generated, and the magnitude of the calculated energy was expressed as an index value. The tear resistance was measured with a method in accordance with JIS LI096. The evaluations were conducted using the results of the belt of Conventional Example 1 as a reference index value of 100. An increase in the index value indicates an improvement in the tear resistance.

[0034]

Impact resistance of central portion in width direction

Cut samples of each conveyor belt were used to evaluate the impact resistance at the central portion in the width direction of the conveyor belt. The impact resistance was evaluated and measured by dropping a weight with a pointed lower end and of a predetermined weight onto the upper cover rubber of a conveyor belt stretched and installed horizontally, and then measuring the drop height when the weight pierced the conveyor belt in the thickness direction. The evaluations were conducted using the results of the belt of Conventional Example 1 as a reference index value of 100. An increase in the index value indicates an improvement in the impact resistance.

[0035]

Creep performance

The creep performance was evaluated by continuously applying a load of a predetermined tensile force in the belt longitudinal direction to each cut sample of the conveyor belt, and then measuring the elongation in the belt longitudinal direction after a predetermined amount of time. The evaluations were conducted using the results of the belt of Conventional Example 1 as a reference index value of 100. An increase in the index value indicates that the elongation through creep has become smaller and is improved.

[0036]

From the results shown in Table 1, it was found that in comparison to the belt of Conventional Example, the belts of Examples 1 to 3 exhibited improved tear resistance at both end portions in the belt width direction, and that the creep performance was equivalent. Furthermore, regarding the impact resistance of the central portion in the width direction, the belt of Example 1 exhibited impact resistance that was equivalent to that of the belt of Conventional

Example, and the belts of Examples 2 and 3 exhibited improved impact resistance in comparison to that of the belt of Conventional Example.

Reference Signs List [0037]

Conveyor belt

Core

Fiber reinforced layer

3a Other fiber reinforced layer

Warp thread

Weft thread

Upper cover rubber

Lower cover rubber

8a, 8b Pulley

Support roller

Object to be conveyed

Claims

Claims [Claim 1]

A fiber reinforced layer for a conveyor belt, the fiber reinforced layer having a woven structure in which warp threads extend in a longitudinal direction, and weft threads extend in a width direction, wherein elongation of the fiber reinforced layer at both end portions in the width direction under a one-tenth load of a breaking load in the longitudinal direction is from 110% to 200% of elongation at a central portion in the width direction.
[Claim 2]

The fiber reinforced layer for a conveyor belt according to claim 1, wherein the woven structure is a 2/2 broken twill structure.
[Claim 3]

The fiber reinforced layer for a conveyor belt according to claim 1 or 2, wherein the warp threads at both end portions in the width direction comprise a polyamide fiber, and the warp threads at the central portion in the width direction comprise a polyester fiber.
[Claim 4]

A conveyor belt, wherein the fiber reinforced layer for a conveyor belt described in any of claims 1 to 3 is embedded as a core with an extension direction of the warp threads oriented in a belt longitudinal direction.
[Claim 5]

The conveyor belt according to claim 4, wherein the core has a multilayer structure in which a plurality of reinforced layers is laminated, and an outermost circumferential reinforced layer of the multilayer structure is the fiber reinforced layer for a conveyor belt.

1/5

FIG. 1

2/5

2(3, 3a)

FIG. 2

3/5

FIG.3

4/5

FIG. 4

5/5

FIG. 5